scholarly journals Analysis of Bearing Characteristics of Energy Pile Group Based on Exponential Model

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6881
Author(s):  
Lichen Li ◽  
Longlong Dong ◽  
Chunhua Lu ◽  
Wenbing Wu ◽  
Minjie Wen ◽  
...  
Keyword(s):  
Analytical Model ◽  
Load Transfer ◽  
Mechanical Response ◽  
Field Tests ◽  
Pile Group ◽  
Exponential Model ◽  
Heating Process ◽  
Thermal Cycles ◽  
Energy Pile ◽  
The Cost

Energy piles are an emerging energy technology for both structural and thermal purposes. To support structure load, piles are always used in groups with raft; however, the cost and complexity of field tests and numerical modelling limits the research on the bearing characteristics of energy pile group. In this paper, exponential model was applied to simulate the thermo-mechanical soil-pile interaction of energy pile group. Axial load transfer (τ-z) analysis was first performed to calculate the shear stress distribution in the soil, then matrix displacement method was introduced to determine the thermo-mechanical response of energy pile group. The validity of the analytical model was tested against field tests and numerical results. A case study was further performed to analyze the influence of thermal cycles and arrangement of thermally active piles on the bearing response of the whole pile group. Test results show that with the thermally activated pile in pile group, (1) differential settlement increases with thermal cycle numbers; (2) the axial force of thermally active pile increases during heating process and decreases during cooling process, and this trend varies for the surrounding nonthermal piles; (3) induced load on thermal pile increases with thermal cycles, but decreases for nonthermal piles. The proposed analytical model is expected to serve as a simple and convenient alternative for the preliminary analysis on the bearing characteristics of energy group pile.

scholarly journals Research on Improving the Durability of Bridge Pavement Using a High-Modulus Asphalt Mixture

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1449
Author(s):  
Wenfeng Wang ◽  
Shaochan Duan ◽  
Haoran Zhu
Keyword(s):  
Construction Industry ◽  
Mechanical Response ◽  
Design Method ◽  
Asphalt Mixture ◽  
Field Tests ◽  
Bottom Layer ◽  
High Modulus ◽  
Practical Applications ◽  
Depth Prediction ◽  
Pavement Structure

In order to improve the durability of the asphalt pavement on a cement concrete bridge, this study investigated the effect of the modulus of the asphalt mixture at the bottom layer on the mechanical response of bridge pavement, along with a type of emerging bridge pavement structure. In addition, the design method and pavement performance of a high-modulus asphalt mixture were investigated using laboratory and field tests, and the life expectancy of the deck pavement structure was predicted based on the rutting deformation. The results showed that the application of a high-modulus asphalt mixture as the bottom asphalt layer decreased the stress level of the pavement structure. The new high-modulus asphalt mixture displayed excellent comprehensive performance, i.e., the dynamic stability reached 9632 times/mm and the fatigue life reached 1.65 million cycles. Based on the rutting depth prediction, using high-modulus mixtures for the bridge pavement prolonged the service life from the original 5 years to 10 years, which significantly enhanced the durability of the pavement structure. These research results could be of potential interest for practical applications in the construction industry.

scholarly journals The increased use value of bamboo leaves as silica source for t-type zeolite synthesis

2018 ◽  
Vol 197 ◽  
pp. 05003 ◽  
Author(s):  
Soni Setiadji ◽  
Citra Deliana Dewi Sundari ◽  
Endang Lala ◽  
Denia Febby Nurbaeti ◽  
Ira Novianti ◽  
...  
Keyword(s):  
Sem Analysis ◽  
High Price ◽  
Heating Process ◽  
Zeolite Synthesis ◽  
X Ray Diffraction ◽  
Cost Performance ◽  
Silica Source ◽  
Bamboo Leaves ◽  
Type Zeolite ◽  
The Cost

T-type zeolite can be used as catalyst, adsorbent, and membranes for gas separation. The synthesis of T-type zeolite needs to be optimized in both of the method and source of precursor, because of its relatively high price. In this research, the synthesis is done using silica extracted from bamboo leaves instead of commercial silica. This increases the value of the bamboo leaves and the cost-performance of zeolite synthesis. The silica was extracted from bamboo leaves ash using alkaline solvent. The extracted silica has 81.76% of purity and an amorphous phase. The T-type zeolite was synthesized using the molar composition of 0.15 Na2O : 0.025 Al : 0.15 K2O : 1 SiO2 : 15 H2O : 0.06 TMAOH, under hydrothermal method and heating process for 4 days, 60°C for 2 days and 120°C for the next 2 days. The characterization method using X-Ray Diffraction and Infra-Red Spectroscopy were performed to confirm the formation of T-type zeolite. The results of Scanning Electron Microscope (SEM) analysis show that the formed T-type zeolite has erionite cylindrical crystal shape.

Interface Engineering of CNT/Polymer Nanocomposites With Tunable Damping Properties

2018 ◽  
Author(s):  
Michela Talò ◽  
Giulia Lanzara ◽  
Maryam Karimzadeh ◽  
Walter Lacarbonara
Keyword(s):  
Load Transfer ◽  
Mechanical Response ◽  
Material Design ◽  
Tensile Tests ◽  
Nanocomposite Films ◽  
Damping Capacity ◽  
Interfacial Region ◽  
Material Damping ◽  
Stick Slip ◽  
Multi Walled Carbon Nanotubes

In this work, the arising of stick-slip dissipation as well as the global mechanical response of carbon nanotube (CNT) nanocomposite films are tailored by exploiting a three-phase nanocomposite. The three phases are represented by the CNTs, a polymer coating localized on the CNTs surface and a hosting matrix. In particular, a polystyrene (PS) layer coats multi-walled carbon nanotubes (MWNTs) that are randomly dispersed in a polyimide (PI) matrix. The coating phase is strongly bonded to the CNTs outer sidewalls ensuring the effectiveness of the load transfer mechanism and reducing the material damping capacity. The coating phase can be thermally-activated to modify, and in particular, decrease the CNT-matrix interfacial shear strength (ISS) thus facilitating the stick-slip onset in the nanocomposite. The ISS decrease finds its roots in a partial degradation of the coating phase and, in particular, in the formation of voids. By weakening the CNT/polymer interfacial region, a significant enhancement in the material damping capacity is observed. An extensive experimental campaign consisting of monotonic and cyclic tensile tests proved the effectiveness of this novel multi-phase material design.

scholarly journals A Comprehensive Review of the Mechanical Behavior of Suspension Bridge Tunnel-Type Anchorage

2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
Yafeng Han ◽  
Xinrong Liu ◽  
Ning Wei ◽  
Dongliang Li ◽  
Zhiyun Deng ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Failure Modes ◽  
Load Transfer ◽  
Mechanical Response ◽  
Soft Rock ◽  
Suspension Bridge ◽  
Development Trend ◽  
Factors Affecting ◽  
Research Results ◽  
Rock Strata

The recent surge of interest towards the mechanical response of rock mass produced by tunnel-type anchorage (TTA) has generated a handful of theories and an array of empirical explorations on the topic. However, none of these have attempted to arrange the existing achievements in a systematic way. The present work puts forward an integrative framework laid out over three levels of explanation and practical approach, mechanical behavior, and calculation method of the ultimate pullout force to compare and integrate the existing findings in a meaningful way. First, it reviews the application of TTA in China and analyzes its future development trend. Then, it summarizes the research results of TTA in terms of load transfer characteristics, deformation characteristics, failure modes, and calculation of ultimate uplift resistance. Finally, it introduces four field model tests in soft rock (mainly mudstone formations), and some research results are obtained. Furthermore, it compares the mechanical behavior of TTA in hard rock strata and soft rock strata, highlighting the main factors affecting the stability of TTA in soft rock formation. This paper proposes a series of focused topics for future investigation that would allow deconstruction of the drivers and constraints of the development of TTA.

scholarly journals Effect of a dual tire pressure on the design parameters of thick asphalt pavements using finite element freeware

DYNA ◽  
2016 ◽  
Vol 83 (196) ◽  
pp. 194-203
Author(s):  
Myriam Rocío Pallares Muñoz ◽  
Julián Andrés Pulecio-Díaz
Keyword(s):  
Finite Element ◽  
Analytical Methods ◽  
Asphalt Pavement ◽  
Field Tests ◽  
Asphalt Pavements ◽  
Design Parameters ◽  
Future Research ◽  
Tire Pressure ◽  
The Cost ◽  
Cost Of Construction

<p>The effect of a dual tire pressure on the design parameters of thick asphalt pavements using finite element freeware EverStressFE©1.0 is evaluated. This is trying to represent more adjusted the footprint shape and intensity of stress generated by the tires of vehicles. To validate the elastic multilayer EverStress©5.0 software was used. The results of the deformations can be concluded that the asphalt pavement designs made with analytical methods may be slightly oversized and consequently increase the cost of construction of pavements. This study marks a route to analyze the sensitivity of various factors that may affect the design of asphalt pavements. Future research is expected to integrate dynamic conditions by introducing results of field tests to full scale.</p>

On the influence of thermal cycles on the yearly performance of an energy pile

2018 ◽  
Vol 16 ◽  
pp. 32-44 ◽  
Author(s):  
Marianna Adinolfi ◽  
Rosa Maria Stefania Maiorano ◽  
Alessandro Mauro ◽  
Nicola Massarotti ◽  
Stefano Aversa
Keyword(s):  
Thermal Cycles ◽  
Energy Pile

Functional tests of the ETCS and rail traffic control systems

2021 ◽  
Vol 133 ◽  
pp. 15-26
Author(s):  
Paweł Drózd ◽  
Adam Rosiński
Keyword(s):  
Traffic Control ◽  
Functional Model ◽  
Field Tests ◽  
Base Layer ◽  
Initial State ◽  
Railway Traffic ◽  
Control Devices ◽  
Traffic Control Devices ◽  
The Cost ◽  
The Impact

The paper presents the issues of railway traffic control devices testing and focuses on European Train Control System (ETCS) devices widely implemented in railways. The functions of the ETCS system, principles of operation are described. The basic telegrams transmitted in the track-to-train relation are listed. The process of designing and verifying the implemented data and what parameters are checked at the stage of field tests using the locomotive is briefly described. The functional model of the SRK devices, including ETCS elements, was presented, and the close relationship between the base layer of the railway traffic control devices and the ETCS was shown. Equipment testing reduces the availability of the rail network, engages staff, and generates costs. A test generation method is presented to minimize the impact. Two indicators are proposed for reducing the set of checks, the cost of checking and the information effectiveness. The cost of checking due to the problematic estimate is generalized, divided into three groups taking into account the difficulty and resource consumption of bringing the devices to the initial state and their operation according to the test. Therefore, the obtained set of checks is suboptimal and ensures complete coverage of the functions with tests, which is essential when testing devices. The tests are carried out using available setting commands and the implementation of tasks - entry and exit routes at the station. The proposed method is universal and can be applied to any railway traffic control device, regardless of the manufacturing technology. It is a non-invasive method in the structure of the tested devices and does not require additional hardware resources.

scholarly journals A Modified Analytical Heat Source Model for Numerical Simulation of Temperature Field in Friction Stir Welding

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Xiangqian Liu ◽  
Yan Yu ◽  
Shengli Yang ◽  
Huijie Liu
Keyword(s):  
Heat Flux ◽  
Friction Stir Welding ◽  
Analytical Model ◽  
Heat Generation ◽  
Tilt Angle ◽  
Temperature Fields ◽  
Analytical Models ◽  
Maximum Temperature ◽  
Thermal Cycles ◽  
Friction Stir

In the conventional analytical model used for heat generation in friction stir welding (FSW), the heat generated at the pin/workpiece interface is assumed to distribute uniformly in the pin volume, and the heat flux is applied as volume heat. Besides, the tilt angle of the tool is assumed to be zero for simplicity. These assumptions bring about simulating deviation to some extent. To better understand the physical nature of heat generation, a modified analytical model, in which the nonuniform volumetric heat flux and the tilt angle of the tool were considered, was developed. Two analytical models are then implemented in the FEM software to analyze the temperature fields in the plunge and traverse stage during FSW of AA6005A-T6 aluminum hollow extrusions. The temperature distributions including the maximum temperature and heating rate between the two models are different. The thermal cycles in different zones further revealed that the peak temperature and temperature gradient are very different in the high-temperature region. Comparison shows that the modified analytical model is accurate enough for predicting the thermal cycles and peak temperatures, and the corresponding simulating precision is higher than that of the conventional analytical model.

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